Japanese Journal of Applied Physics · 1974 · 83 citations · 0 references
Natural SciencesMaterials SciencePhysicsElectronic MaterialsSemiconductor MaterialsSolid State PhysicsDefects In Electronic MaterialsDopingRare-earth-doped MaterialsSemiconductor DefectsSemiconductor Device MaterialsSemiconductor PhysicsBand Emission SpectraDefect ComplexesDefect Levels In SemiconductorsHeat Treatment EffectsSemiconductor CharacterizationSemiconductor DopingStoichiometric EffectsVapor Pressure
Te-doped GaAs crystals were heat-treated under various arsenic vapor pressures, and the defects related to nonstoichiometry were studied. The acceptor density formed by heat treatment shows minimum at a certain arsenic vapor pressure (PAs, min), and the relation between the annealing temperature (TH) and this arsenic vapor pressure PAs, min is given as PAs, min\fallingdotseq2.6×106exp {-1.05 eV/(kTH)} Torr. The density of acceptors related with defects, probably two sorts of acceptors generated at lower pressures and at higher pressures respectively, is at the same time in proportion to the concentration of the initial donor impurity (Te). Therefore complexes associated both with the donor impurity (Te) and with the defects due to the deviation from the stoichiometric composition are formed. These complexes are responsible for both the 0.18 eV acceptor level and the 1.30 eV emission band at 77 K. Furthermore defects with acceptor levels of 0.12 eV and 0.15 eV, are investigated. These defects are unstable and disappear by reannealing at comparatively low temperatures (300–400°C) leaving acceptor levels at 0.18 eV.